Family-run company Enigma specializes in custom titanium, steel, and stainless-steel frames, which are built and finished in its Sussex, England, workspace. It also offers lower-priced stock sizes and complete builds.

The Extensor is one of the company’s premium frames; the one shown here has custom paint and hand-picked components. Beneath the paint lies—uncommon, for a bike—Columbus XCr stainless steel tubes, which offer a ride that’s quite different than the velvety feel most people associate with steel. It’s smooth, but also more than that.

Every stainless-steel Enigma Extensor is built to order.

Trevor Raab

The ride has bite and sharpness. It sings, and sometimes it also growls. You feel stiffness at the bar, saddle, and pedals, and the bike moves with urgency. It’s full and warm, mostly, but at times it felt almost harsh (though it never fully got there). That complexity and those sometimes contradictory sensations are usually found in carbon bikes. But here they are in a metal frame. Enigma indeed.

Built to Order, Worth the Wait

The Extensor is the only stainless-steel frame in Enigma’s line. Because it uses such a niche material, each Extensor is built to order. This means you’ll wait a bit longer to get your bike, but it also means you have more options than what Enigma’s batch-production models have to offer. Stock sizing is, um, stock, but custom sizing is available for a $300 upcharge. Custom finishes are available, too, and price is based on the amount of work required (for example, the polished stays and graphics on our review bike cost $350). Most Extensors are built for rim brakes, but discs are an option: A $400 upcharge gets you a frameset with 12mm thru-axles built for flat-mount calipers.

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Our test bike has polished stays and graphics, a $350 upcharge.

Trevor Raab

Drivetrain Choices Abound

There are few tech surprises on this welded metal frame. It has tidy, hooded, rear dropouts, a threaded bottom bracket, and a 30.9mm seatpost. It can also be prepared for Shimano Di2, Campagnolo EPS, SRAM eTap, FSA WE, or Rotor UNO drivetrain at no additional charge.

Fat, 44mm head tubes (for tapered-steerer forks) often look out of place on steel frames, but subtle machining, the Extensor’s massive down tube, and the Enigma CSIX fork’s wide blades create a more proportionate front end.

Custom Geometry Available

Enigma offers the Extensor in five stock sizes with fairly straightforward, race-style geometry, though the head tubes trend slightly tall. Fully customized geometry is available for an additional $300.

A Selle Italia SLR saddle sits on a Thomson carbon seatpost.

Trevor Raab

Our test bike has Rotor’s UNO hydraulic group; there are four other groups from which to choose.

But with so many other options to choose from, your Extensor can be totally different from the one you see here. According to Enigma’s US importer Michael Musil, “We offer kits from Campagnolo, Shimano, SRAM, FSA, and Rotor. Wheels from Campy, Shimano, Zipp, Lightweight, FSA/VisionTech, 3T, Enve, and others—as well as custom wheels. For cockpit/touch points: our own Enigma/C-Six components, PRO, Ritchey, Deda [Elementi], 3T, Enve, Zipp, and many others. Saddles by Selle Italia, San Marco, Fizik, Fabric, Brooks, and more.”

Ride Impressions

You may be inclined to assume that stainless steel offers the same ride as steel. Surprisingly, it’s distinct. The ride certainly is metal, but it’s not like aluminum or titanium either.

The various connection points of the bike to rider, and rider to road, are very stiff. The bike moves with insistence. It’s full and warm, mostly, with sensations of brittleness around the edges. It rides smoothly, but sometimes doesn’t feel smooth, as though it’s doing one thing, but telling you another. It feels like it should be on the edge of a harsh and jarring ride, yet it’s surprisingly fluid.

The umami-like and contradictory sensations of the Extensor’s ride are usually associated with carbon, yet live here in metal.

All of this begs the question: If carbon is lighter, titanium more fluid, and steel more lively, who is the Enigma Extensor for? Answer: It’s for the person who wants the sharpness of a carbon race bike but the toughness and longevity of titanium, and who doesn’t mind a bit of extra weight. That’s this bike. And that’s who it’s for.

matt phillipsSenior Test Editor, BicyclingMatt is Bicycling’s senior test editor, and has been testing for Bicycling and its related titles since 1995.

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